1. Field of the Invention
The present invention relates to paper feeders, and more particularly to a paper feeder, for example, for use in an image forming apparatus, such as electrostatic transfer copying machines, laser printers and facsimile systems, electronic typewriters, word processors, ADFs for copying machines, and the like.
2. Description of the Prior Art
Conventional copying machines include a paper feed table for placing paper thereon, a transport roller for transporting the paper from the table toward feed rollers, a first arm pivotably supported by the shaft of the transport roller and extending toward the feed table, a delivery roller mounted on the forward end of the arm, a separating roller adapted for contact with the transport roller for preventing feed of more than one sheet of paper at a time, a second arm pivotably supported between the transport roller and the delivery roller, and a shutter attached to the second arm for blocking the paper.
The delivery roller and the shutter are controlled at the same time with a solenoid (see, for example, U.S. Pat. No. 4,089,516) or individually by respective cams each at a proper time.
However, the former method requires a great solenoid for pivotally moving the delivery roller which is heavy and therefore involves the problem that the solenoid makes the machine large-sized.
The latter method requires a drive mechanism for each of the cams, similarly making the apparatus large-sized and necessitating an increased number of parts.